Activated carbon has found use in various applications such as air and water purification, hydrocarbon adsorption in automotive evaporative emission control and cold start hydrocarbon adsorption, etc. Microporous structure carbon (pore diameter less than 20 angstroms and BET surface area of 1000-3000 m.sup.2 /g) are suitable for many applications such as gas phase adsorption e.g. light hydrocarbons and H.sub.2 S, while other applications require larger size of pores in the carbon for optimum adsorption and/or catalytic activity. For example, removal of larger molecular size pollutants such as humine, protein, etc. in liquid phase, in addition to conventional gaseous pollutants, such as hydrocarbons, or certain kinds of pesticides require specific surface properties and pore size distributions. When catalytic or chemical reaction is limited by mass and heat transfer, larger size of pores in the carbon is preferred. Mesoporosity in the carbon is sometimes also required for adequate catalyst loading and dispersion.
Activated carbon monoliths, whether in the form of a coating on a substrate, or a shaped structure of activated carbon, have found use in various applications especially where durability and low pressure drop is required, such as in some chemical reactions using strongly acidic or basic solvents or other corrosive media.
Therefore it would be an advancement in the art to have a method of making activated carbon, especially in the form of honeycombs with various pore sizes to match the particular applications.
The present invention discloses such a method in which activated carbon having microporosity or mesoporosity is produced from pitch.